Question:
What were the observations of Rutherford's ?-scattering experiment?
Answer:
Observations were:
- Most of the α particles passed straight through the gold foil without any deflection.
- Some of the α-particles were deflected by the foil by small angles.
- A very small percentage ( 1 out of 12000) rebound i.e. deflected by wide angles between 90 - 180.
Structure of the Atom
Q 1.
Who discovered electrons?
Q 2.
Who discovered protons?
Q 3.
What do you think would be the observation if the ?-particle scattering experiment is carried out using a foil of a metal other than gold?
Q 4.
Write a short note on Nucleus.
Q 5.
If A = 23 and Z = 11 for Na atom, how many protons, electrons and neutrons present in Na atom?
Q 6.
What were the important features of atomic model based on Rutherford's scattering experiment?
Q 7.
Fill in the blanks :
Rutherford's scattering experiment is related to to the size of ____________.
Q 8.
Describe briefly Thomson's model of an atom.
Q 9.
If an atom contains one electron and one proton, will it carry any charge or not?
Q 10.
Fill in the blanks :
In the three fundamental sub-atomic particles, _________ are negatively charged, _________ are positively charged and ____________ have no charges.
Q 11.
How many times is a proton heavier than an electron ?
Q 12.
Fill in the blanks :
Anode rays are also called ___________.
Q 13.
State the number of electrons present in the outermost shell of the atoms of the following elements :
(i) Neon(ii)Chlorine
Q 14.
Fill in the following blanks
Atomic
number | Mass number | Protons | Neutrons | Electrons | Symbol |
|---|
| 10 | 22 | ....... | ........ | ....... | ........ |
Q 15.
What is the relationship between an atom containing 11 protons, 11 electrons and 11 neutrons, and another atom containing 11 protons, 11 electrons and 12 neutrons ?
Q 16.
Fill in the following blanks in respect of an atom of an element :
No.of
protons | No.of
neutrons | Mass number | Atomic
number | No.of
electrons | Valency |
|---|
| 11 | 12 | ........ | ....... | ........ | ......... |
Q 17.
What is mass number?
Q 18.
What is the maximum number of electrons an M shell of the atom can accommodate ?
Q 19.
Compare an electron, a proton and a neutron in respect of their relative masses and charges.
Q 20.
On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?
Q 21.
Fill in the blanks :
The maximum number of electrons that can be accommodated in L-shell are _______.
Q 22.
Give one use each of the following radioactive isotopes :
(a)Uranium-235 (b) Cobalt-60
Q 23.
What is ionization energy?
Q 24.
Fill in the blanks :
_______ are atoms having the same mass number but different atomic numbers.
Q 25.
Name the scientist who discovered electron.
Q 26.
What is a proton ? How does it differ from a neutron ?
Q 27.
(a) Describe the Rutherford's model of an atom. State one drawback of Rutherford's model of the atom.
(b) The mass number of an element is 23 and it contains 11 electrons. What is the number of protons and neutrons in it ? What is the atomic number of the element ?
Q 28.
State one use of radioactive isotopes in medicine.
Q 29.
What are cathode rays?
Q 30.
What is the maximum number of electrons which can be accommodated in the L shell of an atom
Q 31.
What were the observations of Rutherford's ?-scattering experiment?
Q 32.
Fill in the blanks :
________ rays are negatively charged.
Q 33.
Name the shell of an atom which can accommodate a maximum of
(a) 2 electrons (b) 18 electrons
Q 34.
What is the absolute mass and charge of an electron ?
Q 35.
Which radioactive isotope is used to determine the activity of thyroid gland ?
Q 36.
(a) What are radioactive isotopes ? Give two examples of radioactive isotopes.
(b)Give any two uses of radioactive isotopes.
(c)An element Z contains two naturally occurring isotopes
Z and
Z. If the average atomic mass of this element be 35.5 u, calculate the percentage of two isotopes.
Q 37.
What are canal rays?
Q 38.
Fill in the blanks :
The mass number of an atom is equal to the number of ________ in its nucleus.
Q 39.
Fill in the blanks :
The maximum number of electrons that can be accommodated in K-shell are _______.
Q 40.
Name the particles which actually determine the mass of an atom.
Q 41.
What is the electronic configuration of a hydrogen atom
Q 42.
What is the positive charge on the nucleus of an atom due to ?
Q 43.
Which shell of an atom can accommodate a maximum of
(a) 8 electrons?
Q 44.
What is the absolute mass and charge of a proton ?
Q 45.
State one use of radioactive isotopes in industry.
Q 46.
What are the limitations of Rutherford’s model of the atom?
Q 47.
What is Atomic Number? Who coined this term?
Q 48.
Fill in the blanks :
The _________ of an atom is dense, small in size and is positively charged.
Q 49.
Fill in the blanks :
Atomic number is equal to _____________.
Q 50.
What is the maximum number of electrons that can go into the N shell of an atom ?
